Apparatus for the continuous production of lead oxides in the dry state



Jan. 31, 1933.

G. SHI MADZU APPARATUS FOR THE CONTINUOUS PRODUCTION OF LEAD OXIDES IN THE DRY STATE Original Filed April' 27, 1926 2 Sheets-Sheet l In very-far Jan. 31, 1933. sHlMADZU 1,896,020

APPARATUS FOR THE CONTINUOUS PRODUCTION OF LEAD OXIDES IN THE DRY STATE Original Filed April 27. 1926 2 Sheets-Sheet 2 SE2 8. f

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Patented Jan. 31, 1933' GENZO SHIMADZU,

OF KIO'IO, JAPAN AIPABATUS FOR THE CONTINUOUS PRODUCTION OF LEAD OXIDES IN THE DRY STATE Application filed April 27, 1926, Serial Roi 104,999. Renewed June 31, 1929.

, This invention relates to. an apparatus for the continuous production of lead oxides, the object of the invention being to obtain such oxides in the form of extremely fine powders and in a dry state.

The invention involves the subjection of pieces of metallic lead maintained in a state of a itation to artificially supplied atmospher1c air or other oxidizin gas whereby a lo film or coating of oxide will be formed on the ieces, the formation of the film or coatin ein augmented without fusion of the meta by the heat generated in the principal re: action between metallic lead and the oxidizing gas and by the frictional heat created through rubbing of the pieces one against the other, this rubbing action causin also a brading off as a fine-powder of the oxide thus produced, and the oxidizing gas or a I art thereof being also utilized to carry off t e powder for collection and further treatment if needs Broadly the apparatus of the invention comprises a vessel i adapted to be rotated means for feeding pieces of metallic lea thereto while the vessel is rotating and means for artificially supplying atmosp eric air or other oxidizing gas to the interior of the vessel'in such a manner as to'contact with 7 the surfaces of the pieces of lead to oxidize the same and to take up and convey the.

formed oxide powder as itis abraded by the rubbing action of the pieces a ainst each other to a collector and/or filter evice.

In the appended drawings, I have shown an advanta eous form of apparatusin which Figure 1 orizontal section) represents an oxidizing chamber and Figure 2 (elevation with parts broken away), a dust catching tower.

Referring more particularly to Figure 1 of the drawings, (1 denotes a drum WlllCh for the purpose of permitting rotation is provided with trunnions b, I) supported by bearings c, c. The trunnion b is also journalled in a bearin c? which is so designed as v to form a casing or a worm-wheel d fast on the trunnion b, said worm-wheel being in mesh with a worm d coupled'to a suitable source of power.

.b is a stationary pipe 9 1 1y directed branch The trunnion b is hollow and its interior 1s provided with helical grooves f which as the trunnion rotates function as a screw conveyor f which is supplied withpieces of lead byan automatic feeder e. Trunnion f con- -veys the pieces C to the drum a into which of the drum whilst the latter is rotating. The

air or gas issuing from the nozzles 9 impinges upon the lead pieces in the drum and acts primarily to cause a coatin or film of oxide to be formed thereon. T e trunnion b is also hollow and the inner end of the supply pipe 9 is provided with a nozzle 9 so arranged with res ectto the interior of the trunnion .b as to orm an ejector or exhauster for the drum 0,.

The oxide which in fact is a sub-oxide is formed on the pieces principally by the action of the oxidlzing gas thereon as has been explained, the gas actlng continuously on the surface of the, ieces which are maintained in a state of agitation owing to the rotation of the drum so that all the pieces are properly subjected to the oxidizing action. This oxidation is aided by the heat generated by the reaction itself and also by the friction set up owing to the rubbing of the pieces one against the other. The oxide film or coating is of a comparativel brittle naturev and the continual rubbing o the pieces together due to the rotationalmotion of the drum (1 causes this film or coating to be abraded oil as a suboxide powder, thus exposing fresh surfaces of metallic lead to the action of the oxidizing gas and the other conditions which augment the formation of the oxide film. This a'brading off or removal of the suboxide coating from the pieces of metallic lead is also caused in part by the impinging of the air'from jets g on the surfaces of the pieces of metal lie lead. The air which is fed through pipe 300 g to the nozzles g at relatively high ressure leaves the nozzles at a velocity sufficiently high to blow any oxide from those pieces of lead on which the air impinges. The combined rubbing action of the pieces and action of the jets of air upon the pieces of me tallic lead provides a'very efficacious means of reducing the oxide to a remarkably fine powder, so fine in fact that from tests made it has been proved that the weight of a given volume of the powder is only from one third to one tenth of the weight of the same volume of metallic lead, or less of the weight of the same volume of water. As a further proof of its fineness it is found that the sub-oxide powder will readily convert to litharge in the presence of an oxidizing agent by spontaneous oxidation after the ap licatlon of initial heat. That is to say, i the heat of a match for example be applied momentarily to a quantity of the powder, the combustion will proceed of its own accord until all the powder has been converted to litharge.

The suboxide which is formed in my machine in the above described manner is a very unstable fine owder. It is essential that it be removed om the mill in which it is formed immediatel after it has been ground or blown from the amps of lead. Otherwise if it is permitted to remain within the mill for any appreciable length of time it will go over to litharge inasmuch as the temperature within the mill is sufliciently high and there is a plentiful supply of air present. In

the arran ement shown the powder is removed su stantially instantaneously after formation by the currents of air issuing from jets g which penetrate the entire mass of lead and which leave the mill through trunnion b carryin with it the formed powder. As will be note the interior of trunnion b is flared from the drum to form a nozzle which, combined with the action of the air issuing from jet 9 functions as an ejector to aid in the ra id removal of said powder. A chamber it 18 connected near its upper end to the hollow trunnion b and acts to collect the powdered oxide or a portion of it issuing rom the trunnion. This chamber h is provided with a plurality of vertical bars h which act as a screen or sieve to break down the conveying action of the ejector by impingement of the particles thereagainst so that the particles will fall into the bottom of the chamber and accumulate therein as indicated at A. The sub-oxide powder may be sion will be complete and the product will be uniform throughout due to the fact that the air within the chamber it is in heated condition and while so, heated it has ready access to the powder as it falls on the pile a. Were the su oxide powder first permitted to accumulate in a pile and then oxidized it would be found that the product would not be uniform but that a large ortion on the inside of the pile to which t e air does not have ready access would remain in the suboxide state. To start the oxidation it is necessary to apply external heat to the product but once started the heat generated by the reaction will be sufiicient to oxidize all of the powder which is thereafter formed in the mill and delivered to the chamber h. Any powder intermingled with gas that passes through the screen it is transferred to a bag room or filter tower i where it is finally separated from the gas. This tower is provided with filter bags of suitable material such as silk which are subjected externally to a rarefied atmosphere or vacuum created in the upper art of the tower by means of the exhauster By this means the gas is drawn through the bags leaving the powder on the interior surface thereof from whence it falls and is collected at the bottom ofthe tower as indicated at B. Here again the suboxide powder ma be removed as such at convenient interva s or first converted into litharge. It will be appreciated that if found desirable a plurality of filter towers ma be provided in series whereby the extracte gas may be subjected to further filtration to ensure complete separation of powder. It will also be appreciated that the provision of an initial separator 71. followed by a filter or filters is not essential to the carrying out of the invention. In some cases it might be found that the separator It could be dispensed with in which case the filter stage could be coupled direct to the drum. A ain, the se arator might in some instances e used w1t 1- out a filtration stage. I reserve to myself the right to such modification and others that are obvious in the construction and assembly of the apparatus.

I claim:

1. Apparatus for the production of lead oxides in the dry state, comprising a vessel adapted to be rotated, hollow trunnions supporting said vessel, a screw conveyer disposed in one of said hollow trunnions to introduce material into said vessel, an air pipe passing through said hollow trunnions and terminating in the other of said hollow trunnions whereby air passing through said pipe acts to expel dry material from said vessel throu h said other hollow trunnion.

2. pparatus for the production of lead oxides in the dry state, comprising a vessel adapted to be rotated, hollow trunnions supporting said vessel, a screw conveyer dis- Ill ' faces thereof are posed in one of said hollow trunnions to introduce material into said vessel, an air pipe passing through said hollow trunnions and terminating in the other of said hollow trunnions whereby air passing through said pipe acts to expel dry material from said vessel through said other hollow trunnion, said air pipe having branches thereon provided with nozzles whereby air is also introduced into the interior of the drum.

3. Apparatus for the continuous production of lead oxides in the'dry state, comprising a vessel adapted to be rotated, means for supplying oxidizing gas to the interior of the vessel, an outlet for said gas, and

means comprising an injector for increasin the velocity of said gas as it passes throug said outlet.

4. Apparatus for the continuous production of lead oxides in the dry state, comprising a vessel adapted to be rotated, means for feeding lumps of metallic lead to said vessel, a pipe for feeding air under pressure to said vessel a plurality of jets extending from said pipe to impinge upon said metallic lead pieces within said vessel whereby the suroxidized, means for rotating said vessel to abrade said oxide from said surfaces by mutual attrition, and means for removing said oxide from said vessel substantially instantaneously upon formation.

5. Apparatus for the continuous production of lead oxides in the dry state, comprising a vessel adapted to contain pieces of metallic lead, means for feeding lead to said vessel, a pipe for feeding air underpressure to said vessel, a plurality of jets extending from said pipe to impinge upon the surfaces of said metallic lead pieces within said vessel, whereby the surfaces of said lead pieces are oxidized, means for :rotating said vessel to cause said oxide to be abraded from said pieces by mutual attrition, said vessel having an outlet and means at the end of said pipe extending into said outlet for causin said air to pass through said outlet at as cientlfy high velocity to carrysaid abraded oxide rom said vessel.

6. Apparatus for the continuous production of lead oxides in the dry state, comprising a vessel adapted to be rotated,-means for feeding pieces of metallic lead to said vessel, a pipe for feeding air under pressure to said vessel a plurality of jets extending from said pipe to impinge a ainst the surfaces of said lead pieces where y said surfaces are oxidized and said oxide is blown from said pieces, and an ejector for removing said gas and said oxide from said vessel.

7. Apparatus for the continuous production of lead oxides in the dry state com rising a drum, means for feeding pieces 0 metallic lead to said drum, a conduit extending into said drum and connected to said source of supply of air under pressure, a plurality of nozzles connected to said conduit for causingisaid air to impinge upon said metallic lea pieces within said vessel whereby the s faces of said pieces are oxidized, means f r rotating said drum to grind said oxide from said metallic lead pieces, an e'ector for removing said air and said oxide rom said drum, means interposed in the path of travel of said air and powder for se arating a portion of said powder from said air, and a collector for removing the remainder of said powder from saidair.

.8. Apparatus for the continuous production of lead oxides in the dry state comprising a drum,'a conduit connected to a source of supply. of air under pressure and extending into said drum, a plurality of nozzles connected to said conduit for causing said air to impinge upon said metallic lead pieces within saiddrum, means for rotating said drum, an outlet for saiddrum, an ejector for blowin said product from said drum throug said outlet and a collector connected to said last named means-for supplying said product from said air.

9. Apparatus for the continuous production of a product including litharge in a dry state comprising a vessel rotatable on axes and means extending through an axis for feeding pieces of metallic lead to said vessel, a conduit for feeding an oxidizing gas under pressure to the lower part of said rotatable vessel, said vessel having an outlet above the zone of impact between the oxidizing gas and the lead pieces in the vessel, whereby said oxidizing s oxidizes the surface of the lead pieces an then blows the powdered lead oxides upwardly and outwardly from said surfaces, means for rotating said vessel, a chamber havin a conduit communicating with said rotata le vessel, said chamber having vertically extending fabric filters in its upper portion and a lower portion below said filters into which said oxides ma slide off and fall from the filters to be urther oxidized to litharge and a conduit from the filters to conduct away the oxidizing gas separated by the filters from said oxides.

10. Apparatus for the continuous production of a product including litharge in a dry state com rising an apparatus including a vessel in t e form of a drum, means for feeding pieces of lead into the drum, means for rotating the drum to cause frictional movement between said pieces,-means for supplying under pressure an oxidizing gas to the interior of the drum so as to act on said pieces to form a coatin of lead suboxide thereon and to remove rom the pieces the powder formed by the abrading action of the pieces a ainst one another, and means associated with said apparatus in which said lead tion of litharge in a dry state comprising an apparatus includin a vessel in the form of a drum, means for eeding pieces of lead into the drum, means for rotating the drum to cause frictional movement between said pieces, means for supplying under pressure atmos heric air to the interior of the drum in suc awise as to act on said pieces to form a coating of lead suboxide thereon and to take up and remove from the pieces the powder formed by the abrading action of thepieces against one another, and means associated with said apparatus whereby said lead suboxide is converted into litharge, and means for receiving the product collected from said apparatus In testimony whereof I have aflixed my signature.

GENZO SHIMADZU. 

